1. Field of the Invention
This invention relates to an upsetting device for upsetting the ends of elongated workpieces such as wire pieces, and more particularly for such an upsetting device used for the production of heads on nails.
2. Description of the Prior Art
The state of the art includes upsetting devices having an upsetting tool which is displaceable forwards and backwards by means of a carriage to which it is connected for continuous conjoint movement.
It is already known to construct the upsetting device of an apparatus for the production of wire nails in such a manner that the upsetting tool operates with a short stroke. In such an arrangement, the upsetting action on the head of the wire nail may be derived either from a short stroke crank shaft or from a short stroke cam disc by way of an upsetting carriage. This arrangement has the advantage that a greater length of time is available for shaping the head than in long stroke constructions, with the result that the speed of deformation and the resistance to deformation can be reduced. A softer transition is obtained in the upsetting process without alteration to the operating cycle in the coupling members and the noise level of the machine is therefore reduced.
Short stroke constructions have, however, the disadvantage that owing to the short excursion of the upsetting tool, there is only a very small distance between the clamping jaws which serve as anvil and grip the wire during upsetting of the head and the upsetting tool when the upsetting carriage is in the withdrawn position.
The disadvantage of this connection in short stroke constructions of the carriage is that insufficient space for a tool change is available between the upsetting tool and the workpiece to be upset even when the upsetting tool is withdrawn so that it has hitherto been necessary to dismantle the clamping tools provided for holding the workpiece and then to reassemble them.
In other words, it has hitherto always been necessary to remove the entire box containing the clampinq jaw whenever the upsetting tools, and especially the clamping tools have had to be replaced due to wear and tear or due to a change in the diameter of the wires to be processed.